With regard to an imaging apparatus, such as a digital still camera, an auto-focus for automatically focusing an object preferred by a user is known (for example, Japanese Unexamined Patent Publication No. 2008-309947, and Japanese Patent Publication No. 3500539). The auto-focus includes a single auto-focus for focusing an object one time, a continuous auto-focus for continuously maintaining focused-status after the single auto-focus.
When performing the single auto-focus, an imaging apparatus sets a focus detecting range in a frame (for example, the center of the frame). When the user commands performing the single auto-focus with a preferred object captured in the focus detecting range, the imaging apparatus, changing a focal length of a lens, images in a plurality of the frames. Then, the imaging apparatus, by detecting whether the focus detecting range in the imaged image data is in the focused-status or not, detects the focal length of a lens for focusing on the object, and moves the lens to and fixes it at the focal length. The single auto-focus is performed, at a time of a focus adjustment before imaging a still-image, or immediately after starting imaging a moving-image.
When performing the continuous auto-focus, the imaging apparatus monitors the focused-status of the focus detecting range of the imaged image data in every frame, and, if the focused-status is lost by a displacement of the object, the imaging apparatus performs the single auto-focus. Further, in resent years, an imaging apparatus is proposed which performs an object following continuous auto-focus, whereby the focus detecting range follows an object which displaces from frame to frame.
However, when the continuous auto-focus is performed and the displacement amount of an object is large, there occurs a case that the object is not included in the focus detecting range (or the area included therein is small) despite of the object being included in the frame. In case that the object following continuous auto-focus is performed, processes are necessary such as detecting an object in each frame, and, according to the position thereof, setting the focus detecting range. Therefore, setting the focus detecting range delays by the time required for such a process, and there can be a case that, when the focus detecting range is set, the position of the object displaces from the focus detecting range.
In case that the object is not included in the focus detecting range, if the single auto-focus is performed according to the focused-status of the focus detecting range, not the preferred object but a background in a distance, for example, is focused.